In 2012, the elder Sandusky was convicted of sexually abusing 10 boys over a 15-year period. (Gene J. Puskar/AP)

"While we were fully prepared to proceed to trial, today's guilty plea to all charges ensures a significant prison sentence for defendant's solicitation of child sex crimes with two minors that once completely trusted him," Centre County District Attorney Stacy Parks Miller told Philadelphia's CBS 3 Eyewitness News.

"This outcome also ensures the victims need not suffer the trauma and revictimization of testifying at trial and importantly, the defendant will have to comply with strict sex offender registration requirements for the remainder of his life. We are happy that these girls can move forward and experience a life with adults that deserve their trust," Miller said.

In 2012, the elder Sandusky was convicted of sexually abusing 10 boys over a 15-year period.

He was found guilty on 45 counts of sex abuse and was sentenced to 30 to 60 years in prison.